In general, the formation of thin films on wafers may be divided into physical vapor deposition (PVD) using physical technologies and chemical vapor deposition (CVD) using chemical technologies.
Chemical vapor deposition may use chemical reaction of source materials to form single crystalline semiconductor thin films or insulation layers on a surface of a wafer. The chemical vapor deposition may be broadly classified, according to the pressure of a chamber, into a low pressure chemical vapor deposition (LPCVD), an atmosphere pressure chemical vapor deposition (APCVD), a plasma enhanced chemical vapor deposition (PECVD), and a high pressure chemical vapor deposition (HPCVD).